Avinguda Diagonal is the name of one of Barcelona's most important avenues. It cuts the city in two, diagonally from west to east, hence the name.

Location

It was originally projected by engineer and urban planner Ildefons Cerdà as one of the city's wide avenues, which along with Avinguda Meridiana would cut the rationalist grid he designed for l'Eixample. Both would meet at Plaça de les Glòries Catalanes, which Cerdà envisioned as the new city centre. However, Plaça Catalunya, occupying a more privileged position in the urban area would finally become the centre.

The avenue starts in the Sant Martí district, next to Ronda del Litoral, bordering Sant Adrià de Besòs, and crosses the city finally meeting the Lleida-Madrid highway and Ronda de Dalt, by Esplugues de Llobregat, in Les Corts.

It's consistently 50 m wide and about 11 km long.
 History

Ildefons Cerdà's so-called Pla Cerdà wasn't totally successful in transforming Barcelona's urban reality, as only parts of it were finally approved. The construction of Avinguda Diagonal is one of the projects it entailed that became reality, when a Royal Decree from Queen Isabella II of Spain and O'Donnell's Spanish government in Madrid allowed him to start the construction of the avenue in 1859. The city council of Barcelona had previously requested the approval of Antoni Rovira i Trias's alternative project instead, which had been rejected.

After the completion of its central section, from current Plaça de Francesc Macià towards Glòries, it soon became one of Barcelona's most popular avenues and an ideal place for the Catalan aristocrats and bourgeoisie to exhibit their carriages, and Francesc Cambó, leader of Lliga Regionalista proposed the construction of a new palace for the then monarch Alfonso XIII in 1919 (the royal palace in Ciutat Vella had been destroyed in the fire of 1875).
Names

The different regimes that held power in Catalonia and Spain during the 20th century sought to change the city's street names, and Avinguda Diagonal was no exception to that: it has been known under the following name:

    * Gran Via Diagonal – original name which Ildefons Cerdà and Víctor Balaguer intended to call the avenue.
    * Avinguda d'Argüelles – 1891. Named after Agustín Argüelles.
    * Avinguda de la Nacionalitat Catalana – 1922. Mancomunitat de Catalunya.
    * Avenida de Alfonso XIII –1924. During Primo de Rivera's dictatorship, named after the king Alfonso XIII.
    * Avinguda del Catorze d'Abril – 1931. Second Spanish Republic
    * Gran Vía Diagonal – 1939, provisional name imposed the day after the Fascist capture of Barcelona as an attempt to eliminate references to the Republic.
    * Avenida del Generalísimo Francisco Franco – 1939. During the Authoritarian Regime of Francisco Franco.
    * Avinguda Diagonal – Its current name, adopted following the restoration of democracy in 1979.

It should be noted, though, that in popular usage the name "Diagonal" has always prevailed.